Researchers Hope New HIV Drugs Will Do Less Harm

Jan. 30, 2000 (San Francisco) -- As the AIDS epidemic enters its 20th year, scientists are still searching for new treatments -- drugs that hopefully will dampen the progressively toxic complications of long-term treatment as well as inhibit the relentless progression of HIV. Word is emerging here this week at the Seventh Conference on Retroviruses and Opportunistic Infections of experimental approaches aimed at achieving both goals.

The success of using combinations of drugs to combat HIV is well documented. HIV patients are living longer. However, scientists are finding out that this benefit comes at a price -- over time the virus becomes resistant to the drugs, and patients are experiencing debilitating side-effects to the therapy such as osteoporosis, diabetes, and the accelerated buildup of plaque in their arteries.

Currently, AIDS drugs interfere with two enzymes that are crucial to the life cycle of HIV. Researchers believe the key to overcoming the problems associated with current therapies is to combine them with drugs that target the deadly virus in new ways.

Studies looking at methods to make the current drugs less toxic are encouraging, says David Ho, director of the Aaron Diamond AIDS Research Center in New York.

One study presented Sunday shows just how widespread the side effects of drug therapy really are. In 122 men receiving protease inhibitors for HIV, 21% had various stages of bone loss -- including severe osteoporosis, a disease associated with fractures and bone pain.

Constance Bennett, MD, chairwoman of the conference's scientific program committee, says that the problems associated with HIV therapy is one of the major themes of this year's meeting.

"We're ... going to be focusing on the complications of those therapies. There are major presentations related to identifications of new syndromes that have emerged as a consequence of some of our therapies, interventions that we'll be using to try to alleviate those longer term complications," Bennett told reporters on this first day of the four-day event. Some 3,000 AIDS researchers from around the world are attending.

According to Ho, promising drugs in various stages of development include integrase inhibitors that prevent HIV from inserting its genetic code into human DNA. Also on the horizon are treatments that directly prevent HIV from destroying the immune system. That's the process that starts the inevitable decline into AIDS.

"It's clear from the initial studies that these [new drugs], by blocking this step, [could enable us to] lower the [amount of] virus in the same way that we've done [with the existing therapies]," says Ho.